Use of eosin as a fluorophore in capillary electrophoresis with laser detection

Eosin has been used to generate the background signal far indirect fluorime tric detection of inorganic and organic ions, simultaneously separated by c apillary zone electrophoresis (CZE). This reagent provides constant fluores cence over the pH range of 5-10 and is compatible with the excitation by an argon ion laser at 488 nm with emission at 520 nm. The use of esosine as f luorophore, H3BO3, and Na2B4O7 as electrolyte and diethylentriamine as modi fier of the electroosmotic flow in CZE were optimised. The analytical poten tial of the studied buffer was tested on a group of 12 anions, used as mode l compounds. Both, hydrodynamic and electrokinetic injection mode were opti mised. The detection limits determined by the last injection mode, were in the range 0.008-0.037 mg 1(-1). By using this method, the quantitation of t he common anions in tap and mineral water has been carried out successfully . (C) 2001 Elsevier Science B.V; All rights reserved.